On-line services may provide users with the ability to send and receive instant messages. Instant messages may be exchanged in a private on-line conversation between two or more people who have access to an instant messaging service and who have installed communications software necessary to access and use the instant messaging service. A participant list that includes the communications identities with which a user exchanges instant messages may be displayed for a user and may be used to establish instant messaging sessions with those other identities. The participant list may indicate whether each identity associated with the participant list is on-line.